Gun perforator



Ma an, 1950 J. o. TOW 7 2,509,657

GUN PERFORATOR Filed Aug. 23, 1946 v Xv, I I9 l ////////////mm Patented Mi, so, 1950 can rnarons'ron James 0. Tow, Huntington Park, CallL, assignor to McCullough Tool Company, Los

A selm,

Calif., a corporation 01' Nevada Application August 23, 1948, Serial No. 892,426

Claims. 1

My invention relates to guns for perforating I casing, which has been set in a well, by firing projectiles through the wall of the casing, and relates in particular to a well casing perforating gun of simplified construction, which may be economically manufactured and which is characterized by being simple in operation by reason of the simplified method of firing the propellant charges in the gun.

It is an object of the invention to provide a method and apparatus for perforating a well casing in a well, wherein the propellant charge disposed behind the projectile in the gun body is fired by a flame or pressure produced in the gun bore ahead of the projectile, this flame or pressure passing back along the exterior of the projectile into the chamber which holds the propellant charge, to ignite such propellant charge to drive the projectile out through the gun bore.

Gne of the advantages resulting from the invention is that the gun bore and the propellant receiving chamber may be relatively quickly iormed by simple machining operations, and another is the fact that it is not necessary to provide, in the gun body, passages which communicate through the wall of the gun body ,with the propellant receiving chamber, for the purpose of igniting the propellant charge, as is necessary where the old electrical or fuse and primer firing methods are followed.

It is an object of the invention to provide a method and apparatus wherein the propellant charge lying behind the projectile in the well perforating gun body is ignited by burning a charge of powder or explosive in the gun bore ahead of the projectile and conducting flame or pressure back from the front end of the gun bore to the propellant charge.

A further object of the invention is to provide a method and apparatus for firing a well permrating gun wherein the external or firing charge is exploded by use of an explosive priming cord which is placed on the exterior of the gun body so as to pass across the mouth of the gun bore.

It is a further object of the invention to provide a simple well perforating gun wherein a primer cell is placed adjacent or against the outer end of the projectile in the gun bore, this primer cell being exploded by pressure resulting from the explosion of a primer cord which extends across the mouth of the gun bore, with the result that flame or pressure from the primer cell, discharges from the cell and then rearwardly between the external face of a loose fitting projectile and the bore wall to ignite thepropellant charge disposed adjacent the rear end of the projectile.

A further object of the invention is to provide a well perforating gun wherein the propellant charge is fired as a result of the explosion of a primer charge in the outer portion of the 81111 bore, the projectile having at its rear end a plate with openings therethrough for passage of the flame and pressure from the gun bore into the propellant charge to ignite the same.

A further object of the invention is to provide a well perforating gun of extremely simple form wherein the gun barrel is formed directly in the gun body by drilling of a lateral opening therein and the chamber for receiving the propellant charge is formed by extending rearwardly from the gun bore a, bore of slightly smaller diameter so as to form a shoulder which constitutes a line of division between the gun bore and the propellant receiving chamber and also provides a stop for limiting rearward movement of the projectile and thereby preventing premature explosion of the propellant charge as the result of the projectile being moved rearwardly by externally applied pressure of fluid in the well.

A further object of the invention is to provide a. form wherein the gun bore is in a barrel which is separate from the gun bore, and wherein a delay means is provided in the form of a plate adapted to be sheared when the gun is fired.

Further objects and advantages of the invention may be brought out in the following part of the specification, wherein specific description is for the purpose of making 9. complete disclosure of a preferred embodiment of the invention without placing limitation on the scope of the invention defined in the appended claims.

Referring to the drawings which are for illustrative purposes only,

Fig. l is a partly sectioned fragmentary view showing a portion of the gun body embodying my invention. i

Fig. 2 is a fragmentary section to enlarged scale taken as indicated by the line 2-4 of Fig. 1.

Fig. 3 is an enlarged cross sectional view of the primer cell.

Fig. 4 is a transverse sectional view through a gun body showing an alternative form of construction having an insertable gun barrel.

In Fig. 1 I have shown a portion of a gun body It which, in accordance with the known practice of perforating wells by use of perforating guns, is lowered into the well by use of a suspension means which may be either a cable or a string of tubing. The manner of securing the gun body to the suspension means is not a part of the present invention, and therefore is not shown. This gu'n body III has a number of gun barrels or bores ll formed therein in spaced relation and pointing in different directions in accordance with known practices. Herein the terms "gun bore and gun barrel are substantially synonymous, for the reason that a gun barrel is a wall or metal having an opening through which a projectile is propelled. This wall maybe a separate tube or it may be a part of a unitary gun bodyl In the present instance the gun barrels are formed by boring holes laterally into thecylindrical steel body In.

Each gun barrel ll comprises a bore which extends inwardly from the surface of the gun body II) to an annular shoulder l2 which forms a stop for limiting rearward movement of a pro-' Extending -inchannel I6, which traverses the mouths of thegun barrels II, this channel I6 having thepurpose of receiving an external charge of explosive which in the present practice of the invention comprises an explosive priming cord l'l, portions I8 '01 which extend across the mouths of the barrels ll. As shown in Figs. 1 and 2, small channels l9 are cut in the wall of eachchamber I4, these channels l9 intersecting the shoulders I2.

In each gun barrel ll, ahead of the projectile l3 therein, a firing charge 20 is placed and the outer portion of each gun barrel II is sealed by use of an inserted rubber plug 2 I. After the loading of the chambers I 4, and the placing of the projectile and primer and rubber plug, in the barrels II, the priming cord II is placed in the channel [6, and the upper end of this priming cord is connected to a firing means of any known yp As shown in Fig. 3, each priming charge 20 consists of a primer cell having a frangible cup 25'and an end wall 28, the parts 25 and 26 cooperating to form a chamber which contains an explosive 21 such as nitro-powder, or other exploslve material having similar characteristics. The end wall 26 has in the outer face thereof a recess 28 which receives the extremity of the projectile nose as shown in Fig. l. The wall 26 has also plugged openings. 29 extending therethrough. These openings 29 may be filled with bodies 29', Fig. 3, of any substance which will prevent powder leaking out and will be displaceable by the force of the explosion of the powder 21.

The projectiles l3 are so formed with relation to the openings of the gun barrel that combustion products resulting from the explosion of the priming cells or firing charges 2|! may pass rearward through the gun barrels II along the outer faces of the projectiles l3 and then through the small channels I9 into the propellant charges 15 to ignite the same. A simple way of accomplishing thisresult is to reduce the diameter of the projectiles l3 so that a very small space will be left between the projectiles l3 and walls of the gun barrels l I.

By used the gun assembly shown in Fig. 1, it is possible to perform my new method of firing the propellant charges of a well perforating gun by exploding a firing charge in the gun barrel or bore ahead of the projectile, passing combustion products, such as gases and flames, rearwardly in the front portions of the gun barrels ahead of the projectiles into the propellant charges to ignite the same. The method I have shown for exploding the firing charges, consisting of the primer cells 20, comprises the explosion of an externally placed explosive consisting specifically of the priming cord IT. The forces of the explosion of the portions I8 of the priming cord I! drive the priming cells 20- inward,

4 rupturing the cups 25 and exploding ing the charges 21 therein. Then the products of combustion from the explosion of the powder charges 21 pass rearwardly through the openings 29 and thence rearwardly through the gun barrels 11, past the projectiles n and through the channels I9 into the propellant charges ll, exploding these charges so that the projectiles I3 will be propelled at high velocity out through the gun barrels II and through the wall of the casing which is to be perforated.

In the alternative form of my invention shown in Fig. 4, a gun body Illa is provided with an I internally threaded recess 30 which receives an externally threaded cylindric barrel member 3| having a gun bore Ila. At the rear end of the recess there is a cavity forming a propellant receiving chamber 32. this chamber 32 there is an outwardly faced shoulder 33.

In this form of the invention a projectile aswhich may be separate from the projectile Ila.

or may be integrally formed therewith. The peripheral portion of this plate 40 is clamped between the shoulder 33 and the rear end of the a barrel member 3|. It has several small openings or passages 32 therethrough disposed so as to connect the rear end of the bore Ila with the chamber 32. In the use of this form of the invention a propellant charge 43 is placed in the chamber 32. The plate 40, the projectile I3a, and the barrel member 3I are theninstalled. As in the form of the invention shown in Fig. 1, a firing charge or priming cell 20 is placed in the bore Ila adjacent the outer end of the projectile l3a and a sealing plug 2| is inserted to seal the outer end of the bore Ila. In the same manner as described with relation to Fig. 1, a priming cord I1 is placed so that it will pass across the mouth of the bore Ila externally thereof.

When the external explosive,-consisting of the priming cord I'l, Fig. 4, is exploded, the force derived therefrom explodes the priming cell 20 and combustion products therefrom pass rear- Wardly through the bore Ila, around the exterior of the projectile I3a and then through the ignition passages 42 in the plate 40 to ignite the propellant charge 43. The force of the explosion developed in the burning of the propellant charge 43 shears the plate 40 and drives the projectile l3a at high velocity out through the bore Ila.

In both forms of the. invention disclosed herein the gun structure is of extremely simple form, and the method of firing, though safe and simple, is very effective.

I claim as my invention:

1. In a gun mechanism for perforating well casing, the combination of: a gun body having a propellant chamber with a propellant charge therein, a gun barrel,and a projectile therein, with wall forming an ignition passage leading from the interior of the barrel ahead of said projectile into said propellant chamber and means for limiting the rearward movement of said projectile; a firing charge in the gun barrel ahead of the projectile; and means for exploding said firing charge whereby combustion products therefrom will travel through said ignition passage and ignite said propellant charge.

2. In a gun mechanism for perforating well casing, the combination of: a gun body having a propellant chamber with a propellant charge therein, a gun barrel, and a projectile therein,

or detonat- Around the front end of 8 the opening of said barrel and the exterior of said projectile being cooperatively formed so as to provide an ignition passage leading from the interior of the barrel ahead of said projectile into said propellant chamber and means for limiting the rearward movement of said projectile; a firing charge in the gun barrel ahead of the projectile; and means for exploding said firing charge whereby combustion products therefrom will travel through said ignition passage and ignite said propellant charge.

3. In a gun mechanism for perforating well casing, the combination of: a gun body having a propellant chamber with a propellant charge therein, a gun barrel, anda projectile therein, with walls forming an ignition passage leading from the interior of the barrel ahead of said projectile intosaid propellant chamber and means for limiting the rearward movement of said projectile; a firing charge in the gun barrel ahead of the projectile; and an explosive priming cord extending across the mouth of the barrel so that the explosion of said priming cord will explode said firing charge whereby combustion products therefrom will travel through said ignition passage and ignite said propellant charge.

4. In a gun mechanism for perforating well casing. the combination of; a gun body having a propellant chamber with a propellant charge therein, a gun barrel. and a projectile therein, the opening of said barrel and the exterior of said projectile being cooperatively formed so as to provide an ignition passageleading from the interior of the barrel ahead of said projectile into said propellant chamber and means for limiting the rearward movement of said projectile; a firing charge in the gun barrel ahead of the projectile; and an explosive priming cord extending across the mouth of the barrel so that the explosion of said priming cord will explode said firing charge whereby combustion products therefrom will travel through said ignition passage and ignite said propellant charge.

5. In a gun mechanism for perforating well casing, the combination of:' a gun body having a propellant chamber with a propellant charge therein, a gun barrel, and a projectile, therein, with walls forming an ignition passage leading from the interior of the barrel ahead of said projectile into said propellant chamber and means for limiting the rearward movement of said projectile; a firing charge disposed externally Of the projectile so that combustion products therefrom will pass rearwardly in said gun barrel; and means for exploding said firing charge whereby combustion products therefrom will travel.

through said ignition passage and ignite said propellant charge.

6. In a gun mechanism for perforating well casing, the combination of: a gun body having a propellant chamber with a propellant charge therein, a gun barrel, and a projectile therein, the opening of said barrel and the exterior or said projectile being cooperatively formed so as to provide an ignition passage leading from the interior of the barrel ahead of said projectile into said propellant chamber and means for limiting the rearward movement or said projectile; a firing charge disposed externally oi the projectile '0 that combustion products therefrom will pass rearwardly in said gun barrel; and means for exploding said firing charge whereby combustion products therefrom will travel through said ignition passage and ignite said propellant charge.

7. In a gun mechanism for perforating well casing, the combination of: a gun body having a propellant chamber with a propellant charge therein, a gun barrel, and a projectile therein, with walls forming an ignition passage leading from the interior of the barrel ahead of said projectile into said propellant chamber and means for limiting the rearward movement of said projectile; a unitary primer cell inserted in said barrel ahead of said projectile; means for sealing said barrel; and means for applying inward force against said primer cell to explode the same, whereby combustion products therefrom will travel through said ignition passage and ignite said propellant charge.

8. In a gun mechanism for perforating well casing, the combination of a gun body having a propellant chamber with a propellant charge therein, a gun barrel, and a projectile therein, the opening of said barrel and the exterior 01 said projectile being cooperatively formed so as to provide an ignition passage leading from the interior of the barrel ahead of said projectile into said propellant chamber and means for limiting the rearward movement of said projectile; a unitary primer cell inserted in said barrel ahead of said projectile; means for sealing said barrel; and means for applying inward force against said primer cell to explode the same, whereby combustion products therefrom will travel through said ignition passage and ignite said propellant charge.

9. In a gun mechanism for perforating well casing, the combination of: a gun body having a gun bore extending inwardly from a side thereof to receive a projectile, a cavity forming a propellant charge chamber rearwardly of said gun bore, there being a shoulder between said bore and said cavity to limit rearward movement of said projectile in said gun bore and there being a channel in the wall of said propellant charge chamber leading rearwardly from said shoulder, said gun bore being so formed with relation to the exterior of the projectile to be used therein as to permit a rearward flow of combustion products past the projectile when a firing charge is exploded ahead of the projectile.

10. In a gun mechanism for perforating well casing, the combination of a gun body having a recess extending therein from the side wall thereof and a propellant receiving cavity at the inner end or said recess, there being an outwardly faced shoulder at the front end of said cavity; a removable barrel member securable in said recess, said barrel member having a gun bore; a projectile unit having a projectile body insertable into the rear end of said gun bore; and a flange plate extending radially so as to lie between said shoulder and the rear end of said barrel member, there being an ignition passage through said plate and said projectile body being so formed with relation to said gun bore as to permit explosive products to pass rearwardly along the exterior of the projectile body through said ignition passage when an explosive is exploded ahead of said projectile body so that the combustion products therefrom pass rearwardly in said gun bore.

JAMES O. TOW.

No references cited. 

